Spectral Properties of the Solar Background Velocity Field
We study the scaling properties of time series of Doppler images obtained in good seeing conditions with the San Fernando Observatory 28 cm vacuum telescope and vacuum spectroheliograph in video spectra-spectroheliograph mode. The images correspond to two areas of quiet Sun near disk center taken at 60 second intervals from one hour to six hour spans at ~ 2 arcsec resolution. After removal of 5 min acoustic oscillations the time-spatial spectrum of the velocity is calculated. To study the turbulence of photospheric flows we estimate two scaling parameters: the exponent of the spatial part of the power spectrum and the exponent governing the scaling of time correlations of each spatial mode. The implied diffusive behavior produced by the solar convection in the mesogranulation scale range is discussed. This includes characterization of the type of diffusion involved and the fractal dimension of the diffusion front.